SEOUL, Oct. 10 (Yonhap) -- Special forces of the North Korean Army conducted drills for several days in mid-September to infiltrate the South Korea-U.S. Combined Forces Command in Seoul by paraglider, defense officials said Tuesday.

A paraglider is easy to operate, with its equipment weighing a mere 3 to 4 kilograms. North Korean special forces could carry their folded paragliders on their backs and paraglide from a summit to seize a target in a surprise attack.

It is the first time members of North Korean special forces have carried out paragliding infiltration drills aimed at the allies' command post.

This file photo from April 2017 shows North Korean special forces taking part in a military parade to mark the 105th birthday of the North's late founder, Kim Il-sung. (Yonhap)

According to the officials, North Korean paragliding soldiers participated in the drills at a training ground that has a model building of the Combined Forces Command.

It was already known that they had built a model of the South Korean presidential office Cheong Wa Dae to conduct drills to sharpen their ability to sneak into the South.

The drills using paragliders involved several teams of special forces from the North's Army, Navy and Air Force, they said.

A defense source expressed the worry that the South Korean Army's radar would hardly detect a nighttime airborne attack by North Korean paragliding soldiers, saying, "A paraglider flies at a low altitude without making a sound. It could be useful for making a surprise attack, like a drone."

The source continued, "I believe that North Korean special forces are adopting amazing methods of infiltration with limited resources."

Another defense source said the North Korean drills with paragliders had prompted the South Korean and U.S. forces to conduct their joint short-range air defense drill late last month.

The exercise involved South Korea's air defense unit and soldiers from the U.S. 6th Battalion, 52nd Air Defense Artillery Regiment. It was held in Pocheon, north of Seoul, with no specific date given.

This marked the first time that the allies held a combined short range air defense training drill in South Korea.

The short range air defense, also known as SHORAD, is aimed at effectively countering inbound low-altitude aerial threats like North Korean jets, transports and helicopters.